Why does nitrogen exist as N₂ while phosphorus exists as P₄?

1. The tendency to form pπ–pπ bonds decreases on moving up the group.
2. The tendency to form pπ–pπ bonds decreases on moving down the group.
3. The tendency to form dπ–dπ bonds decreases on moving down the group.
4. The tendency to form dπ–dπ bonds decreases on moving up the group.

Subtopic:  Group 15 - Preparation, Properties & Uses |
 79%
Level 2: 60%+
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Which of the following correctly explains why oxygen can participate in hydrogen bonding whereas chlorine generally does not?

1. Chlorine has a bigger size and as a result, a higher electron density per unit volume.
2. Oxygen has a smaller size and as a result, a lower electron density per unit volume.
3. Oxygen has a smaller size and as a result, a higher electron density per unit volume.
4. Oxygen has a bigger size and as a result, a higher electron density per unit volume.

Subtopic:  Group 16 - Preparation, Properties & Uses |
 74%
Level 2: 60%+
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Which of the following statements regarding the uses of noble gases is/are correct?
1. Neon gas is filled in discharge tubes with characteristic colours.
2. Neon gas is used in beacon lights.
3. Argon along with nitrogen is used in gas-filled electric lamps.
4. All of the above.
Subtopic:  Group 18 - Preparation, Properties & Uses |
 92%
Level 1: 80%+
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Which of the following correctly explains why NH₃ forms hydrogen bonds whereas PH₃ does not?

1. Phosphorus is more electronegative as compared to nitrogen.
2. Nitrogen is more electronegative as compared to phosphorus.
3. Nitrogen and phosphorous have equal electronegativity.
4. Nitrogen is more stable as compared to phosphorus.

Subtopic:  Group 15 - Preparation, Properties & Uses |
 90%
Level 1: 80%+
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Which of the following oxyacids of phosphorus contains two direct P–H bonds?

1. \(\mathrm{H}_3 \mathrm{PO}_2\)

2. \(\mathrm{H}_3 \mathrm{PO}_3\)

3. \(\mathrm{H}_3 \mathrm{PO}_4\)

4. \(\mathrm{H}_4 \mathrm{P}_2 \mathrm{O}_7\)

Subtopic:  Group 15 - Preparation, Properties & Uses |
 79%
Level 2: 60%+
AIPMT - 1999
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Select the correct option based on statements below:
Assertion (A): The valency and oxidation number of sulphur in S8 respectively are 2 and 0.
Reason (R): S8 Rhombic is the most stable allotropic form of sulphur.
  
1. Both (A) and (R) are true and (R) is the correct explanation of (A).
2. Both (A) and (R) are true but (R) is not the correct explanation of (A).
3. (A) is true but (R) is false.
4. Both (A) and (R) are false.
Subtopic:  Group 16 - Preparation, Properties & Uses |
 72%
Level 2: 60%+
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Select the correct option based on statements below:
Assertion (A): The atomic size of F is smaller than that of Cl.
Reason (R): F-F bond is stronger than the Cl-Cl bond.
  
1. Both (A) and (R) are true and (R) is the correct explanation of (A).
2. Both (A) and (R) are true but (R) is not the correct explanation of (A).
3. (A) is true but (R) is false.
4. (A) is false but (R) is true.
Subtopic:  Group 17 - Preparation, Properties & Uses |
 66%
Level 2: 60%+
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Select the correct option based on the statements below:
Assertion (A): NaCl reacts with concentrated H2SO4 to give colourless fumes with a pungent smell. But on adding MnO2, the fumes become greenish-yellow.
Reason (R): MnO2 oxidizes HCl to chlorine gas which is greenish-yellow.
  
1. Both (A) and (R) are True and (R) is the correct explanation of (A).
2. Both (A) and (R) are True but (R) is not the correct explanation of (A).
3. (A) is True but (R) is False.
4. (A) is False but (R) is True.
Subtopic:  Group 17 - Preparation, Properties & Uses |
 85%
Level 1: 80%+
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Select the correct option based on statements below:
Assertion (A): Both rhombic and monoclinic sulphur exist as S8 but oxygen exists as O2.
Reason (R): Oxygen forms  pπ   -   pπ multiple bonds due to its small size and small bond length but  pπ   -   pπ bonding is not possible in sulphur.
    
1. Both (A) and (R) are True and (R) is the correct explanation of (A).
2. Both (A) and (R) are True but (R) is not the correct explanation of (A).
3. (A) is True but (R) is False.
4. Both (A) and (R) are False.
Subtopic:  Group 16 - Preparation, Properties & Uses |
 73%
Level 2: 60%+
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(a) XeF6 + 3H2O →

(b) XeF6 + H2O →

The products formed in the above reactions, respectively, are:

1. XeO3 , XeOF4
2. XeO6 , XeOF4
3. XeO3, XeOF6
4. XeO6 , XeOF6

Subtopic:  Group 18 - Preparation, Properties & Uses |
 81%
Level 1: 80%+
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